Spoke length calculations

Joel said:

Its time to rebuild my rear wheel.
I am re-using my Shimano 6500 rear hub, and a new Velocity Aerohead OC
rim.
Wheel is 28 hole, 3 cross. I ran Spocalc and got the folowing results,
it looks like I can use 295mm for both sides. Does this seem right?

Rear Wheel Input Data Output Data
N, total number of spokes 28 cross left length right length
ERD, effective rim diameter 598.0 0 277.2 276.3
OSB, offset spoke bed 4.0 1 279.6 278.7
WL, width from center to left flange 37.1 2 286.1 285.3
WR, width from center to right flange 20.9 3 295.4 294.6
dL, left flange diameter 45.0 4 305.3 304.5
dR, right flange diameter 45.0 2.25 288.3 287.4
S, spoke hole diameter 2.6
X, cross number (decimal allowed)(optional) 2.25
WL_effective = W - OSB 33.1
WR_effective = W + OSB 24.9

Thanks - Joel

I think you would be better served to use 2 cross with 286 mm left and 284 mm right with these rims and hubs.
If you use 3 cross I think you will need 294 mm right and 295(4) left.

Joel said:

Its time to rebuild my rear wheel.
I am re-using my Shimano 6500 rear hub, and a new Velocity Aerohead OC
rim.
Wheel is 28 hole, 3 cross. I ran Spocalc and got the folowing results,
it looks like I can use 295mm for both sides. Does this seem right?

Rear Wheel Input Data Output Data
N, total number of spokes 28 cross left length right length
ERD, effective rim diameter 598.0 0 277.2 276.3
OSB, offset spoke bed 4.0 1 279.6 278.7
WL, width from center to left flange 37.1 2 286.1 285.3
WR, width from center to right flange 20.9 3 295.4 294.6
dL, left flange diameter 45.0 4 305.3 304.5
dR, right flange diameter 45.0 2.25 288.3 287.4
S, spoke hole diameter 2.6
X, cross number (decimal allowed)(optional) 2.25
WL_effective = W - OSB 33.1
WR_effective = W + OSB 24.9

28h is more commonly two-cross.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Joel said:

Its time to rebuild my rear wheel.
I am re-using my Shimano 6500 rear hub, and a new Velocity Aerohead OC
rim.
Wheel is 28 hole, 3 cross. I ran Spocalc and got the folowing results,
it looks like I can use 295mm for both sides. Does this seem right?

Rear Wheel Input Data Output Data
N, total number of spokes 28 cross left length right length
ERD, effective rim diameter 598.0 0 277.2 276.3
OSB, offset spoke bed 4.0 1 279.6 278.7
WL, width from center to left flange 37.1 2 286.1 285.3
WR, width from center to right flange 20.9 3 295.4 294.6
dL, left flange diameter 45.0 4 305.3 304.5
dR, right flange diameter 45.0 2.25 288.3 287.4
S, spoke hole diameter 2.6
X, cross number (decimal allowed)(optional) 2.25
WL_effective = W - OSB 33.1
WR_effective = W + OSB 24.9

Thanks - Joel

Nothing wrong with 28/3 cross with the understanding that more of the
spoke will overlap on the hub flange. I use 1mm longer on the left side
using a OC rim, not 2mm...

Yer numbers confuse me but Find the right side length, round up, add
1mm to the left.

294/295 is what I think...

It is currently laced 3X. The spokes do come close to touching the head
of the adjacent spoke in the hub flange. I think the reason I laced it
3X is because I previously built a 28H front wheel 2X with DT
Revolution spokes and the spokes started breaking right away. I showed
the wheel to someone I know at a LBS who is a good wheel builder and he
said the spokes were breaking because of where they were crossing over
each over relative to the location of the transisiton of spoke from
thick to thin. After this bad experience with 2X I have always used 3X.
I guess if had not used those Revolution spokes I would have continued
to use 2X on the rear wheel. Im sure those spokes have their place, Im
just not sure where. I also found them to be very stretchy and hard to
true because they would wind up torsionally. I always use DT 14/15
spokes now.

Thanks - Joel

Joel said:

Its time to rebuild my rear wheel.
I am re-using my Shimano 6500 rear hub, and a new Velocity Aerohead OC
rim.
Wheel is 28 hole, 3 cross. I ran Spocalc and got the folowing results,
it looks like I can use 295mm for both sides. Does this seem right?

Rear Wheel Input Data Output Data
N, total number of spokes 28 cross left length right length
ERD, effective rim diameter 598.0 0 277.2 276.3
OSB, offset spoke bed 4.0 1 279.6 278.7
WL, width from center to left flange 37.1 2 286.1 285.3
WR, width from center to right flange 20.9 3 295.4 294.6
dL, left flange diameter 45.0 4 305.3 304.5
dR, right flange diameter 45.0 2.25 288.3 287.4
S, spoke hole diameter 2.6
X, cross number (decimal allowed)(optional) 2.25
WL_effective = W - OSB 33.1
WR_effective = W + OSB 24.9

Yes, you can use 295s on both sides. I use
<http://www.bikeschool.com/spokes/index.cgi> for the calculation.